GARDENER'S MAILBAG: What can I do for my Mexican petunia?
Dear Neil: In your answers addressing lawn weeds you often suggest using 2,4-D products in turf. Most lawns also have trees. I remember using that or some similarly named product to kill mesquite trees at the farm back in the 60s. Is it to be used as a spot spray, or can it be applied to a lawn that has lots of weeds in both bermuda and St. Augustine?
Many products were being used that many years back. My dad was doing brush control research (including mesquite) for Texas A&M at that time, and I helped in the testing, so I got to see a lot of those product names. If you buy a product labeled as a broad-leafed weedkiller for use in controlling weeds such as dandelions, clover and poison ivy, among scores of other non-grassy weeds, it can be applied in a large tank sprayer to open areas or as a pump sprayer to smaller spot targets. I prefer to use the 2-gallon pump sprayers when I am treating my own lawn, both because it allows me to use far less active ingredient and also because it lets me make much more precise applications. I read and follow label directions to avoid damage to desirable trees and shrubs nearby.
Dear Neil: I hope my photo is more than a thumbnail so you can see it. It’s of my Mexican petunia that I planted because I see it growing at a local restaurant where it is thriving. My plant, however, has to be watered twice a day or it wilts as you can see. It’s listed as drought-tolerant, but able to be grown in wetlands (quite a disparity). How can all that be? What can I do to help my plant?
There are those out there who are thinking, “Be careful what you wish for, since Mexican petunias grow so aggressively.” What you have read is all true – both sides of the story.
It appears, looking at your photo, that you may not have done extensive bed preparation for it. I see things growing around it that look like they’ve been there all spring. Some could even be weeds. Did you rototill to a depth of 6-8 inches and work in several inches of organic matter to provide the best possible soil? That, plus watering it by hand deeply until it gets established (often the first summer) will be requirements. It’s a great plant (if you can keep it from spreading). But it will need good soil and ample moisture at the outset. Afternoon shade also helps.
Dear Neil: I have long, brown streaks of grass running through my St. Augustine. It seems to be a pattern that started last year. I tried a fungicide last year. Then I thought it might be the freeze, but it’s showing up exactly as last year. Do you have any ideas?
I do not have specific solutions, but I do have a couple of hunches. It looks like you have a dog, based on the fact that the water dish is right in the middle of one of the browned areas. I’m wondering if the dog goes on patrol in these pathways and wears out your St. Augustine. I see another dog dish at the end of another one of them. Brown patch is the fall disease problem with St. Augustine, but it rarely shows up as elongated patches like this, and take all root rot is the spring issue, but it does not show up in linear patterns. In this rare case the photos didn’t do much to narrow the possibilities. I would suggest Googling around university websites for information and photos of chinch bug damage, gray leaf spot, white grub worms and the two things that I mentioned to see if you can get closer to an answer.
Dear Neil: Three of my trees have holes in their trunks, and an app tells me I have long-horned beetles. How do I get rid of, or treat them?
Your app left you at the altar, didn’t it! Go online and search “university entomology long-horned borers.” You will be absolutely amazed at all the different types of these curious beetles there are. Most specific to one particular species of tree or another. And, each will have its own method of control (some have none). For many, application of a pyrethroid insecticide at precise timing for the species and its life cycle will help. And there are other labeled insecticides. For other species, predatory insects will help. The University of Kentucky has a very good publication on the subject, ENT-43: Insect Borers of Trees and Shrubs by Daniel A Potter and Michael F. Potter. As you work to control them, however, know that keeping your plants vigorous is first and foremost, and know that borers are some of the most challenging of all insect pests.
Dear Neil: What is the best plant to replace 15 Indian hawthorns that were lost in the cold? I have green hollies to the east, abelias to the west. This bed faces north and is shaded half of the time. I’d like something with color. I can prune it if I have to.
Remember that flowering shrubs generally bloom only one or two times per year, and most are deciduous. I would always prefer a shrub that looks great 52 weeks out of the year, even if it was simply evergreen. Dwarf Burford holly would be my choice, hoping that that’s not the “green holly” you have nearby. If it is, I’m going to send you to a Texas Certified Nursery Professional for help. Somebody needs to see the actual landscape. It’s somewhat akin to asking an interior decorator to finish a room in your house when he or she can’t really see the room. Oh, by the way, dwarf Burford holly bears large, bright red berries all winter each winter.
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